There is known, as an image forming apparatus, a printer detachably provided with a cartridge having a developing roller.
Further, there is known, as a cartridge detachably mounted to such a printer, a developing cartridge provided with an electrically-conductive member electrically connected to a contact portion provided in a main casing in order to apply developing bias to a developing roller.
Such a developing cartridge is inserted into the main casing to bring the electrically-conductive member into pressure contact with the contact portion by its resilient force to thereby connect the electrically-conductive member and the contact portion.